Summary

Specify the default implementation of the non-abstract SelectorProvider::inheritedChannel method.

Problem

The non-abstract java.nio.channels.spi.SelectorProvider::inheritedChannel method does not specify its default implementation, thus requiring all implementers to provide their own implementation - even if that implementation is the same as the default. The current, and longstanding, behaviour is to return null.

Solution

Specify the default implementation returns null.

Specification

diff --git a/src/java.base/share/classes/java/nio/channels/spi/SelectorProvider.java b/src/java.base/share/classes/java/nio/channels/spi/SelectorProvider.java
index 4aee1cf41c8..87ada1a15b2 100644
--- a/src/java.base/share/classes/java/nio/channels/spi/SelectorProvider.java
+++ b/src/java.base/share/classes/java/nio/channels/spi/SelectorProvider.java
@@ -292,24 +292,27 @@ public abstract class SelectorProvider {
      * returned. Subsequent invocations of this method return the same
      * channel. </p>
      *
+     * @implSpec The default implementation of this method returns
+     * {@code null}.
+     *
      * @return  The inherited channel, if any, otherwise {@code null}.
      *
      * @throws  IOException
      *          If an I/O error occurs
      *
      * @throws  SecurityException
      *          If a security manager has been installed and it denies
      *          {@link RuntimePermission}{@code ("inheritedChannel")}
      *
      * @since 1.5
      */
     public Channel inheritedChannel() throws IOException {
         return null;
     }